class_docstr: A standard class for monitoring the progress of a VTK algorithm.
  
  This must be use in a ``with`` context and it will block keyboard
  interrupts from happening until the exit event as interrupts will crash
  the kernel if the VTK algorithm is still executing.
  
  Parameters
  ----------
  algorithm
      VTK algorithm or filter.
  
  message : str, default: ""
      Message to display in the progress bar.
docstr: Enter event for ``with`` context.
docstr_tok: ["Enter","event","for","``","with","``","context","."]
code: def __enter__(self):
      """Enter event for ``with`` context."""
      from tqdm import tqdm
  
      # check if in main thread
      if threading.current_thread().__class__.__name__ == "_MainThread":
          self._old_handler = signal.signal(signal.SIGINT, self.handler)
      self._progress_bar = tqdm(
          total=1,
          leave=True,
          bar_format="{l_bar}{bar}[{elapsed}<{remaining}]",
      )
      self._progress_bar.set_description(self.message)
      self.algorithm.AddObserver(self.event_type, self)
      return self._progress_bar
  
imports: import collections
  import logging
  import os
  import re
  import signal
  import sys
  import threading
  import traceback
  from pyvista.core import _vtk_core
label_desc: Use image node_id 4 for calling the ProgressMonitor obj's underlying member method code with example usage: obj.__enter__() and returns: self